US 4,046,693 AGranted

Scum skimmer apparatus

AssigneeHarsco Corporation

InventorNolan S. Glover

Life of this patent

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Abstract

Scum skimmer apparatus having a skimmer blade slideably disposed on support rods extending downwardly from an oscillating bridge which is moveable over the clarifying tank in a biological waste treatment plant. An air tight ballast chamber is secured to the skimmer blade having a source of air communicating with the ballast chamber, the source having a valve for controlling the air flow. As the bridge moves toward the scum trough at one end of the clarifying tank the air is evacuated from the ballast chamber, allowing the blade to engage the surface of the liquid. Upon moving away from the scum trough air is pumped into the ballast chamber providing a buoyancy force which raises the skimmer blade away from the surface. When the opposite end of the clarifying tank is reached the skimmer blade is lowered back to the water by venting the air out of the ballast chamber. A circular treatment tank is provided having spaced concentric walls with partitions therebetween forming alternate aeration and clarifier zones on the periphery thereof with a central digester zone such that separate aeration zones may be used for organic carbon removal and nitrogen removal.

Claims20

Dependent claims

In a clarifier tank for removing microorganisms and waste from liquid influent:

a tank having first and second ends joined by side walls;
a bridge;
means moveably mounting the bridge over the tank;
drive means to move said bridge from a position adjacent the first end of the tank to a second position adjacent the second end of the tank;
means to alternately reverse the direction of movement of the bridge between the first and second ends of the tank;
a skimmer blade;
a ballast chamber having an open lower end submersible below the level of liquid in the tank;
means for rigidly securing the ballast chamber to the skimmer blade;
means for slideably attaching the ballast chamber to the bridge for movement in a vertical direction such that the ballast chamber and skimmer blade move in a horizontal direction with the bridge but are free to move in a vertical direction relative to the bridge to move the skimmer blade out of contact with the liquid;
air supply means communicating with the interior of the ballast chamber above the liquid level therein;
a valve to control the flow of air into and out of the ballast chamber such that air may be injected under pressure into the ballast chamber to raise the ballast chamber upwardly in the liquid, and air may be vented from the ballast chamber through the valve to lower the ballast chamber into the liquid;
actuating means adjacent the first end to control the valve means to move the valve to a position to admit air under pressure into the chamber;
and actuating means adjacent the second end of the tank to move the valve to a position to exhaust air from the chamber.

10 more elements

In a device for removing scum from the surface of liquid in a clarifier tank having first and second spaced end walls, joined by spaced side walls;

liquid in said tank;
a bridge moveably mounted on the side walls;
reversible drive means for moving the bridge between the end walls;
means to alternately reverse the drive means as the bridge reaches the end walls;
at least one ballast chamber;
means slideably suspending the ballast chamber to the bridge;
said chamber being open at the lower end and extending below the level of liquid in said tank;
conduit means communicating with the chamber to supply air under pressure to the area of the chamber above the level of the liquid and to exhaust air therefrom to change the buoyancy thereof;
valve means in said conduit to control the flow of air under pressure through the conduit to said area, and to control the exhaust of air through said conduit from said area;
means to selectively actuate the valve means adjacent each end wall to direct flow of air into and out of said area;
whereby the ballast chamber is alternately raised and lowered;
and a skimmer blade secured to the ballast chamber in position to contact the surface of the liquid when the ballast chamber is in lowered position and to clear the surface of the liquid when the ballast chamber is in raised position.

9 more elements

A clarifier tank having a first and second end walls, said clarifier tank being adapted to contain liquid;

a support bridge moveable between the end walls;
drive means to move the support bridge back and forth between the end walls;
a skimmer blade;
means moveably securing said skimmer blade to said support bridge such that the skimmer blade is moveable vertically relative to the support bridge;
a buoyant member secured to the skimmer blade, said buoyant member being biased by air;
and means to control the buoyancy of the buoyant member to raise the skimmer blade out of contact with the surface of the liquid in the tank adjacent the first end wall as the skimmer blade is moved in one direction by the support bridge and to lower the skimmer blade into contact with the surface of the liquid in the tank adjacent the second end wall as the skimmer blade is moved in the other direction by the support bridge.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/608,286Filed 27 Aug 1975
Granted: 6 Sep 1977
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

C02F 3/1247
Small compact installations for use in homes, apartment blocks, hotels or the like: comprising circular tanks with elements, e.g. decanters,…
B01D 21/00
Separation of suspended solid particles from liquids by sedimentation
B01D 21/14
With moving scrapers: with rotating scrapers
B01D 21/18
Separation of suspended solid particles from liquids by sedimentation: construction of the scrapers or the driving mechanisms for settling tanks